What Is Melanoma?

Because it
often goes undetected, and can metastasize to other organs and areas of the
body, melanoma is the most dangerous of skin cancers. Though not the most
common skin cancer (it accounts for only about five percent of skin cancer
cases), melanoma does cause the most
deaths. The John Wayne Cancer Institute (JWCI) reports the alarming statistics:
“While most cases [of melanoma] are discovered early when cure is likely, about
30 percent of patients will die of the disease.” Cases in the United States
have been growing in recent decades, with an estimated 68, 130 new cases
reported in 2010, according to the American Cancer Society (ACS).

Understanding Your Skin

Your skin is
not simply a protective shell or covering, like a blanket. It is the largest
organ in your body, and serves a variety of essential functions such as
protecting other organs, warding off germs, controlling body temperature, and guarding
you from harmful ultraviolet (UV) rays.

There are
three layers of the skin:

epidermis: top layer, which protects the other layers and the organs

dermis: middle
layer

subcutaneous tissue: bottom layer

If you were
to examine a cross-section of the epidermis,
you would see layers, tiered like a slice of cake, with the topmost layer
protecting the other layers and the organs, and the bottom one made up of basal
cells.

The
outermost layer sheds dead cells, which get replaced by new ones. Here, too, is
another type of cell, melanocyte, responsible
for producing the brown pigment, melanin.
It’s melanin that gives skin a tan or brown color and protects the skin from
the sun. Melanocytes, however, can develop into melanoma.

Melanoma can
appear on normal skin, or it may form on an existing mole or other area that
has changed in appearance. Some moles, present at birth, can develop into
melanoma as well. If the melanoma is detected early, before the tumor has the
chance to spread, it is much more likely to be cured.

Types of Melanoma

According to
the National Cancer Institute, “the three major types of skin cancer are the
highly curable basal cell carcinoma, squamous cell carcinomas and the more
serious malignant melanoma.” Melanoma can further be divided into categories.

The four
major types of melanoma include:

Superficial spreading melanoma: The most common type, accounting for about
70-75 percent of cases, according to the American Melanoma Foundation (AMF). Usually
flat and irregular in shape and color, this form appears in different shades of
black, brown, and purple, and is most common among Caucasians.

Nodular melanoma:
This type typically starts as a raised area, in dark blackish-blue or
bluish red (although some have no color) with irregular borders, and is more
common among men.

Lentigo maligna melanoma:
This type usually appears in the elderly as sun-damaged skin on the face,
neck, and arms; it shows up as a pigmented lesion that grows over time into
flat areas ranging in color from tan to dark brown or black. According to the AMF,
it is “three times more common in females.”

Acral lentiginous melanoma:
The least common form, it usually appears on the palms, soles of the feet,
and under the nails, and is more common in African Americans.

What to Look For

Melanoma
starts in the melanocytes, which are located in the layer of basal cells found
in the deepest part of the epidermis. Though typically of a brown or black
color, melanoma can also be tan, pink, or white. Melanoma usually appears first
on the chest or back in men, and on the legs in women.